1 /* Structure for saving state for a nested function.
2 Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
23 #if !defined(NULL_TREE) && !defined(tree)
24 typedef union union_node
*_function_tree
;
25 #define tree _function_tree
27 #if !defined(NULL_RTX) && !defined(rtx)
28 typedef struct rtx_def
*_function_rtx
;
29 #define rtx _function_rtx
35 enum machine_mode promoted_mode
;
37 struct var_refs_queue
*next
;
40 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
41 Each element describes one pending sequence.
42 The main insn-chain is saved in the last element of the chain,
43 unless the chain is empty. */
47 /* First and last insns in the chain of the saved sequence. */
49 tree sequence_rtl_expr
;
50 struct sequence_stack
*next
;
53 extern struct sequence_stack
*sequence_stack
;
55 /* Stack of single obstacks. */
57 struct simple_obstack_stack
59 struct obstack
*obstack
;
60 struct simple_obstack_stack
*next
;
65 /* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
66 After rtl generation, it is 1 plus the largest register number used. */
69 /* Lowest label number in current function. */
70 int x_first_label_num
;
72 /* The ends of the doubly-linked chain of rtl for the current function.
73 Both are reset to null at the start of rtl generation for the function.
75 start_sequence saves both of these on `sequence_stack' along with
76 `sequence_rtl_expr' and then starts a new, nested sequence of insns. */
80 /* RTL_EXPR within which the current sequence will be placed. Use to
81 prevent reuse of any temporaries within the sequence until after the
82 RTL_EXPR is emitted. */
83 tree sequence_rtl_expr
;
85 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
86 Each element describes one pending sequence.
87 The main insn-chain is saved in the last element of the chain,
88 unless the chain is empty. */
89 struct sequence_stack
*sequence_stack
;
91 /* INSN_UID for next insn emitted.
92 Reset to 1 for each function compiled. */
95 /* Line number and source file of the last line-number NOTE emitted.
96 This is used to avoid generating duplicates. */
98 const char *x_last_filename
;
100 /* A vector indexed by pseudo reg number. The allocated length
101 of this vector is regno_pointer_flag_length. Since this
102 vector is needed during the expansion phase when the total
103 number of registers in the function is not yet known,
104 it is copied and made bigger when necessary. */
105 char *regno_pointer_flag
;
106 int regno_pointer_flag_length
;
108 /* Indexed by pseudo register number, if nonzero gives the known alignment
109 for that pseudo (if regno_pointer_flag is set).
110 Allocated in parallel with regno_pointer_flag. */
111 unsigned char *regno_pointer_align
;
113 /* Indexed by pseudo register number, gives the rtx for that pseudo.
114 Allocated in parallel with regno_pointer_flag. */
115 rtx
*x_regno_reg_rtx
;
118 /* For backward compatibility... eventually these should all go away. */
119 #define reg_rtx_no (cfun->emit->x_reg_rtx_no)
120 #define seq_rtl_expr (cfun->emit->sequence_rtl_expr)
121 #define regno_reg_rtx (cfun->emit->x_regno_reg_rtx)
122 #define seq_stack (cfun->emit->sequence_stack)
124 #define REGNO_POINTER_ALIGN(REGNO) (cfun->emit->regno_pointer_align[REGNO])
125 #define REGNO_POINTER_FLAG(REGNO) (cfun->emit->regno_pointer_flag[REGNO])
129 /* Number of units that we should eventually pop off the stack.
130 These are the arguments to function calls that have already returned. */
131 int x_pending_stack_adjust
;
133 /* Under some ABIs, it is the caller's responsibility to pop arguments
134 pushed for function calls. A naive implementation would simply pop
135 the arguments immediately after each call. However, if several
136 function calls are made in a row, it is typically cheaper to pop
137 all the arguments after all of the calls are complete since a
138 single pop instruction can be used. Therefore, GCC attempts to
139 defer popping the arguments until absolutely necessary. (For
140 example, at the end of a conditional, the arguments must be popped,
141 since code outside the conditional won't know whether or not the
142 arguments need to be popped.)
144 When INHIBIT_DEFER_POP is non-zero, however, the compiler does not
145 attempt to defer pops. Instead, the stack is popped immediately
146 after each call. Rather then setting this variable directly, use
147 NO_DEFER_POP and OK_DEFER_POP. */
148 int x_inhibit_defer_pop
;
150 /* If PREFERRED_STACK_BOUNDARY and PUSH_ROUNDING are defined, the stack
151 boundary can be momentairly unaligned while pushing the arguments.
152 Record the delta since last aligned boundary here in order to get
153 stack alignment in the nested function calls working right. */
154 int x_stack_pointer_delta
;
156 /* Nonzero means __builtin_saveregs has already been done in this function.
157 The value is the pseudoreg containing the value __builtin_saveregs
159 rtx x_saveregs_value
;
161 /* Similarly for __builtin_apply_args. */
162 rtx x_apply_args_value
;
164 /* List of labels that must never be deleted. */
167 /* Postincrements that still need to be expanded. */
171 #define pending_stack_adjust (cfun->expr->x_pending_stack_adjust)
172 #define inhibit_defer_pop (cfun->expr->x_inhibit_defer_pop)
173 #define saveregs_value (cfun->expr->x_saveregs_value)
174 #define apply_args_value (cfun->expr->x_apply_args_value)
175 #define forced_labels (cfun->expr->x_forced_labels)
176 #define pending_chain (cfun->expr->x_pending_chain)
177 #define stack_pointer_delta (cfun->expr->x_stack_pointer_delta)
179 /* This structure can save all the important global and static variables
180 describing the status of the current function. */
184 struct function
*next_global
;
185 struct function
*next
;
187 struct eh_status
*eh
;
188 struct stmt_status
*stmt
;
189 struct expr_status
*expr
;
190 struct emit_status
*emit
;
191 struct varasm_status
*varasm
;
193 /* For function.c. */
195 /* Name of this function. */
197 /* Points to the FUNCTION_DECL of this function. */
200 /* Number of bytes of args popped by function being compiled on its return.
201 Zero if no bytes are to be popped.
202 May affect compilation of return insn or of function epilogue. */
205 /* Nonzero if function being compiled needs to be given an address
206 where the value should be stored. */
209 /* Nonzero if function being compiled needs to
210 return the address of where it has put a structure value. */
211 int returns_pcc_struct
;
213 /* Nonzero if the current function returns a pointer type. */
216 /* Nonzero if function being compiled needs to be passed a static chain. */
219 /* Nonzero if function being compiled can call setjmp. */
222 /* Nonzero if function being compiled can call longjmp. */
225 /* Nonzero if function being compiled can call alloca,
226 either as a subroutine or builtin. */
229 /* Nonzero if function being compiled receives nonlocal gotos
230 from nested functions. */
232 int has_nonlocal_label
;
234 /* Nonzero if function being compiled has nonlocal gotos to parent
236 int has_nonlocal_goto
;
238 /* Nonzero if function being compiled contains nested functions. */
239 int contains_functions
;
241 /* Nonzero if the function being compiled issues a computed jump. */
242 int has_computed_jump
;
244 /* Nonzero if the current function is a thunk (a lightweight function that
245 just adjusts one of its arguments and forwards to another function), so
246 we should try to cut corners where we can. */
249 /* If function's args have a fixed size, this is that size, in bytes.
251 May affect compilation of return insn or of function epilogue. */
254 /* # bytes the prologue should push and pretend that the caller pushed them.
255 The prologue must do this, but only if parms can be passed in
257 int pretend_args_size
;
259 /* # of bytes of outgoing arguments. If ACCUMULATE_OUTGOING_ARGS is
260 defined, the needed space is pushed by the prologue. */
261 int outgoing_args_size
;
263 /* This is the offset from the arg pointer to the place where the first
264 anonymous arg can be found, if there is one. */
267 /* Nonzero if current function uses varargs.h or equivalent.
268 Zero for functions that use stdarg.h. */
271 /* Nonzero if current function uses stdarg.h or equivalent.
272 Zero for functions that use varargs.h. */
275 /* Quantities of various kinds of registers
276 used for the current function's args. */
277 CUMULATIVE_ARGS args_info
;
279 /* If non-zero, an RTL expression for the location at which the current
280 function returns its result. If the current function returns its
281 result in a register, current_function_return_rtx will always be
282 the hard register containing the result. */
285 /* The arg pointer hard register, or the pseudo into which it was copied. */
286 rtx internal_arg_pointer
;
288 /* Language-specific reason why the current function cannot be made
290 const char *cannot_inline
;
292 /* Nonzero if instrumentation calls for function entry and exit should be
294 int instrument_entry_exit
;
296 /* Nonzero if memory access checking be enabled in the current function. */
297 int check_memory_usage
;
299 /* Nonzero if stack limit checking should be enabled in the current
303 /* Number of function calls seen so far in current function. */
304 int x_function_call_count
;
306 /* Nonzero if this function is being processed in function-at-a-time
307 mode. In other words, if all tree structure for this function,
308 including the BLOCK tree, is created before RTL generation
310 int x_whole_function_mode_p
;
312 /* Nonzero if the back-end should not keep track of expressions that
313 determine the size of variable-sized objects. Normally, such
314 expressions are saved away, and then expanded when the next
315 function is started. For example, if a parameter has a
316 variable-sized type, then the size of the parameter is computed
317 when the function body is entered. However, some front-ends do
318 not desire this behavior. */
319 int x_dont_save_pending_sizes_p
;
321 /* List (chain of TREE_LIST) of LABEL_DECLs for all nonlocal labels
322 (labels to which there can be nonlocal gotos from nested functions)
324 tree x_nonlocal_labels
;
326 /* List (chain of EXPR_LIST) of stack slots that hold the current handlers
327 for nonlocal gotos. There is one for every nonlocal label in the
328 function; this list matches the one in nonlocal_labels.
329 Zero when function does not have nonlocal labels. */
330 rtx x_nonlocal_goto_handler_slots
;
332 /* List (chain of EXPR_LIST) of labels heading the current handlers for
334 rtx x_nonlocal_goto_handler_labels
;
336 /* RTX for stack slot that holds the stack pointer value to restore
338 Zero when function does not have nonlocal labels. */
339 rtx x_nonlocal_goto_stack_level
;
341 /* Label that will go on parm cleanup code, if any.
342 Jumping to this label runs cleanup code for parameters, if
343 such code must be run. Following this code is the logical return
347 /* Label that will go on function epilogue.
348 Jumping to this label serves as a "return" instruction
349 on machines which require execution of the epilogue on all returns. */
352 /* List (chain of EXPR_LISTs) of pseudo-regs of SAVE_EXPRs.
353 So we can mark them all live at the end of the function, if nonopt. */
354 rtx x_save_expr_regs
;
356 /* List (chain of EXPR_LISTs) of all stack slots in this function.
357 Made for the sake of unshare_all_rtl. */
358 rtx x_stack_slot_list
;
360 /* Chain of all RTL_EXPRs that have insns in them. */
361 tree x_rtl_expr_chain
;
363 /* Label to jump back to for tail recursion, or 0 if we have
364 not yet needed one for this function. */
365 rtx x_tail_recursion_label
;
367 /* Place after which to insert the tail_recursion_label if we need one. */
368 rtx x_tail_recursion_reentry
;
370 /* Location at which to save the argument pointer if it will need to be
371 referenced. There are two cases where this is done: if nonlocal gotos
372 exist, or if vars stored at an offset from the argument pointer will be
373 needed by inner routines. */
374 rtx x_arg_pointer_save_area
;
376 /* If the function returns non-void, we will emit a clobber of the
377 return registers just in case the user fell off the end without
378 returning a proper value. This is that insn. */
379 rtx x_clobber_return_insn
;
381 /* Offset to end of allocated area of stack frame.
382 If stack grows down, this is the address of the last stack slot allocated.
383 If stack grows up, this is the address for the next slot. */
384 HOST_WIDE_INT x_frame_offset
;
386 /* List (chain of TREE_LISTs) of static chains for containing functions.
387 Each link has a FUNCTION_DECL in the TREE_PURPOSE and a reg rtx
388 in an RTL_EXPR in the TREE_VALUE. */
389 tree x_context_display
;
391 /* List (chain of TREE_LISTs) of trampolines for nested functions.
392 The trampoline sets up the static chain and jumps to the function.
393 We supply the trampoline's address when the function's address is
396 Each link has a FUNCTION_DECL in the TREE_PURPOSE and a reg rtx
397 in an RTL_EXPR in the TREE_VALUE. */
398 tree x_trampoline_list
;
400 /* Insn after which register parms and SAVE_EXPRs are born, if nonopt. */
401 rtx x_parm_birth_insn
;
403 /* Last insn of those whose job was to put parms into their nominal
405 rtx x_last_parm_insn
;
407 /* 1 + last pseudo register number possibly used for loading a copy
408 of a parameter of this function. */
409 unsigned int x_max_parm_reg
;
411 /* Vector indexed by REGNO, containing location on stack in which
412 to put the parm which is nominally in pseudo register REGNO,
413 if we discover that that parm must go in the stack. The highest
414 element in this vector is one less than MAX_PARM_REG, above. */
415 rtx
*x_parm_reg_stack_loc
;
417 /* List of all temporaries allocated, both available and in use. */
418 struct temp_slot
*x_temp_slots
;
420 /* Current nesting level for temporaries. */
421 int x_temp_slot_level
;
423 /* Current nesting level for variables in a block. */
424 int x_var_temp_slot_level
;
426 /* When temporaries are created by TARGET_EXPRs, they are created at
427 this level of temp_slot_level, so that they can remain allocated
428 until no longer needed. CLEANUP_POINT_EXPRs define the lifetime
430 int x_target_temp_slot_level
;
432 /* This slot is initialized as 0 and is added to
433 during the nested function. */
434 struct var_refs_queue
*fixup_var_refs_queue
;
437 int all_types_permanent
;
438 struct momentary_level
*momentary_stack
;
439 char *maybepermanent_firstobj
;
440 char *temporary_firstobj
;
441 char *momentary_firstobj
;
442 char *momentary_function_firstobj
;
443 struct obstack
*current_obstack
;
444 struct obstack
*function_obstack
;
445 struct obstack
*function_maybepermanent_obstack
;
446 struct obstack
*expression_obstack
;
447 struct obstack
*saveable_obstack
;
448 struct obstack
*rtl_obstack
;
450 /* For integrate.c. */
452 int no_debugging_symbols
;
453 /* This is in fact an rtvec. */
454 void *original_arg_vector
;
455 tree original_decl_initial
;
456 /* Last insn of those whose job was to put parms into their nominal
458 rtx inl_last_parm_insn
;
459 /* Highest label number in current function. */
460 int inl_max_label_num
;
462 /* Nonzero if the current function uses the constant pool. */
467 /* Nonzero if the current function uses pic_offset_table_rtx. */
468 int uses_pic_offset_table
;
469 /* tm.h can use this to store whatever it likes. */
470 struct machine_function
*machine
;
471 /* The largest alignment of slot allocated on the stack. */
472 int stack_alignment_needed
;
473 /* Preferred alignment of the end of stack frame. */
474 int preferred_stack_boundary
;
476 /* Language-specific code can use this to store whatever it likes. */
477 struct language_function
*language
;
481 /* If some insns can be deferred to the delay slots of the epilogue, the
482 delay list for them is recorded here. */
483 rtx epilogue_delay_list
;
486 /* The function currently being compiled. */
487 extern struct function
*cfun
;
489 /* A list of all functions we have compiled so far. */
490 extern struct function
*all_functions
;
492 /* For backward compatibility... eventually these should all go away. */
493 #define current_function_name (cfun->name)
494 #define current_function_pops_args (cfun->pops_args)
495 #define current_function_returns_struct (cfun->returns_struct)
496 #define current_function_returns_pcc_struct (cfun->returns_pcc_struct)
497 #define current_function_returns_pointer (cfun->returns_pointer)
498 #define current_function_needs_context (cfun->needs_context)
499 #define current_function_calls_setjmp (cfun->calls_setjmp)
500 #define current_function_calls_alloca (cfun->calls_alloca)
501 #define current_function_calls_longjmp (cfun->calls_longjmp)
502 #define current_function_has_computed_jump (cfun->has_computed_jump)
503 #define current_function_contains_functions (cfun->contains_functions)
504 #define current_function_is_thunk (cfun->is_thunk)
505 #define current_function_args_info (cfun->args_info)
506 #define current_function_args_size (cfun->args_size)
507 #define current_function_pretend_args_size (cfun->pretend_args_size)
508 #define current_function_outgoing_args_size (cfun->outgoing_args_size)
509 #define current_function_arg_offset_rtx (cfun->arg_offset_rtx)
510 #define current_function_varargs (cfun->varargs)
511 #define current_function_stdarg (cfun->stdarg)
512 #define current_function_internal_arg_pointer (cfun->internal_arg_pointer)
513 #define current_function_return_rtx (cfun->return_rtx)
514 #define current_function_instrument_entry_exit (cfun->instrument_entry_exit)
515 #define current_function_check_memory_usage (cfun->check_memory_usage)
516 #define current_function_limit_stack (cfun->limit_stack)
517 #define current_function_uses_pic_offset_table (cfun->uses_pic_offset_table)
518 #define current_function_uses_const_pool (cfun->uses_const_pool)
519 #define current_function_cannot_inline (cfun->cannot_inline)
520 #define current_function_epilogue_delay_list (cfun->epilogue_delay_list)
521 #define current_function_has_nonlocal_label (cfun->has_nonlocal_label)
522 #define current_function_has_nonlocal_goto (cfun->has_nonlocal_goto)
524 #define max_parm_reg (cfun->x_max_parm_reg)
525 #define parm_reg_stack_loc (cfun->x_parm_reg_stack_loc)
526 #define cleanup_label (cfun->x_cleanup_label)
527 #define return_label (cfun->x_return_label)
528 #define save_expr_regs (cfun->x_save_expr_regs)
529 #define stack_slot_list (cfun->x_stack_slot_list)
530 #define parm_birth_insn (cfun->x_parm_birth_insn)
531 #define frame_offset (cfun->x_frame_offset)
532 #define tail_recursion_label (cfun->x_tail_recursion_label)
533 #define tail_recursion_reentry (cfun->x_tail_recursion_reentry)
534 #define arg_pointer_save_area (cfun->x_arg_pointer_save_area)
535 #define rtl_expr_chain (cfun->x_rtl_expr_chain)
536 #define last_parm_insn (cfun->x_last_parm_insn)
537 #define context_display (cfun->x_context_display)
538 #define trampoline_list (cfun->x_trampoline_list)
539 #define function_call_count (cfun->x_function_call_count)
540 #define temp_slots (cfun->x_temp_slots)
541 #define temp_slot_level (cfun->x_temp_slot_level)
542 #define target_temp_slot_level (cfun->x_target_temp_slot_level)
543 #define var_temp_slot_level (cfun->x_var_temp_slot_level)
544 #define nonlocal_labels (cfun->x_nonlocal_labels)
545 #define nonlocal_goto_handler_slots (cfun->x_nonlocal_goto_handler_slots)
546 #define nonlocal_goto_handler_labels (cfun->x_nonlocal_goto_handler_labels)
547 #define nonlocal_goto_stack_level (cfun->x_nonlocal_goto_stack_level)
549 /* The FUNCTION_DECL for an inline function currently being expanded. */
550 extern tree inline_function_decl
;
552 /* Given a function decl for a containing function,
553 return the `struct function' for it. */
554 struct function
*find_function_data
PARAMS ((tree
));
556 /* Pointer to chain of `struct function' for containing functions. */
557 extern struct function
*outer_function_chain
;
559 /* Set NOTE_BLOCK for each block note in the current function. */
560 extern void identify_blocks
PARAMS ((void));
562 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
563 and create duplicate blocks. */
564 extern void reorder_blocks
PARAMS ((void));
566 /* Set BLOCK_NUMBER for all the blocks in FN. */
567 extern void number_blocks
PARAMS ((tree
));
569 /* Return size needed for stack frame based on slots so far allocated.
570 This size counts from zero. It is not rounded to STACK_BOUNDARY;
571 the caller may have to do that. */
572 extern HOST_WIDE_INT get_frame_size
PARAMS ((void));
573 /* Likewise, but for a different than the current function. */
574 extern HOST_WIDE_INT get_func_frame_size
PARAMS ((struct function
*));
576 /* These variables hold pointers to functions to
577 save and restore machine-specific data,
578 in push_function_context and pop_function_context. */
579 extern void (*init_machine_status
) PARAMS ((struct function
*));
580 extern void (*mark_machine_status
) PARAMS ((struct function
*));
581 extern void (*save_machine_status
) PARAMS ((struct function
*));
582 extern void (*restore_machine_status
) PARAMS ((struct function
*));
583 extern void (*free_machine_status
) PARAMS ((struct function
*));
585 /* Likewise, but for language-specific data. */
586 extern void (*init_lang_status
) PARAMS ((struct function
*));
587 extern void (*mark_lang_status
) PARAMS ((struct function
*));
588 extern void (*save_lang_status
) PARAMS ((struct function
*));
589 extern void (*restore_lang_status
) PARAMS ((struct function
*));
590 extern void (*free_lang_status
) PARAMS ((struct function
*));
592 /* Save and restore status information for a nested function. */
593 extern void save_tree_status
PARAMS ((struct function
*));
594 extern void restore_tree_status
PARAMS ((struct function
*));
595 extern void restore_emit_status
PARAMS ((struct function
*));
596 extern void free_after_parsing
PARAMS ((struct function
*));
597 extern void free_after_compilation
PARAMS ((struct function
*));
599 extern void init_varasm_status
PARAMS ((struct function
*));
600 extern void free_varasm_status
PARAMS ((struct function
*));
601 extern void free_emit_status
PARAMS ((struct function
*));
602 extern void free_stmt_status
PARAMS ((struct function
*));
603 extern void free_eh_status
PARAMS ((struct function
*));
604 extern void free_expr_status
PARAMS ((struct function
*));
606 extern rtx get_first_block_beg
PARAMS ((void));
609 extern void diddle_return_value
PARAMS ((void (*)(rtx
, void*), void*));
610 extern void clobber_return_register
PARAMS ((void));
611 extern void use_return_register
PARAMS ((void));
614 extern void init_virtual_regs
PARAMS ((struct emit_status
*));
616 /* Called once, at initialization, to initialize function.c. */
617 extern void init_function_once
PARAMS ((void));